Production of continuous wave-trains by means of primary spark-circuits.



R. G. GALLETTI. I

PRODUCTION OF GOIITIIIUOUS WAVE TRAINS BY MEANS GP PRIMARY SPARK CIRCUITS. APPLICATION FILED JUNE 24, 1910.

1,000,397, Patented Aug. 15, 1911 2 SHEETQ-SHBBT 1.

l I Q l I: 1 l

R. C. GALLETTI.

PRODUCTION OF CONTINUOUS WAVE TRAINS BY MEANS OF PRIMARY SPARK CIRCUITS.

APPLICATION FILED JUNE 24, 1910.

Z SHEETSSHEET 2.

1,000,397, Patented Aug. 15, 1911.

trains by means of primary spar UNITE STATES PATENT OFFICE.

ROBERTO CLEMENS GASLLIETTI, OF LYON, FRANCE.

PRODUCTION OF CONTINUOUS WAVE-TRAINS BY MEANS OF PRIMARY SPARK-CIRCUITS.

vTo all whom it may concern: I Be it known. that I, ROBERTO C. GAL- LETTI, asubjectof the King. of Italy, resid- This invention relates to an apparatus for producing permanent continuous wave k discharges.

The chief feature of the. invention con- ;sists in the said spark discharges being produced quickly or continuously following each other. In the drawings: Figures 1, 3 and 4 show, diagrammatically, apparatus for carrying out the invention. Fig.- 2 shows a representation of the action of myapparatus.

In Fig. 1 I show how a series of primary sparks can influence an aerial conductor or antennaprovidedin a secondary circuit and these condensers intended to emit in space the oscillation energy produced by thesparks. -The; device is constituted by a number of condensers of equal capacities, 0,, 0,, c f 0,, and by 'a condenser 0 which can be e ual to the preceding ones, or different -t erefrom.

have one and the same armature C. A coil L forming the primary of an induction coil is connected at one end to the individual armature of the condenser 0 to which is-also connected the lead M of the high tension continuous current 'machine D, and the other end of thecoil L is connected by means of spark gaps 8,, s sf, 8,, to the condensers 0 c, 0 o an the, latter are connected by'equal resistances WW r lation circuit consists of an earthed, aerial conductor ,or antenna A and of a 0011 L wound about the coil L, the coil ,L being in}- .fluencd by all oscillations produced in the 0 (foil L, spark gap 8 and condenser 0 condenser'c coll L, spark gap 81 and con- All v 1"", and the lead N to the other 'poleofthe dynamo. The secondary oscil- These primary Specification of Letters Patent. Patented Ai gf- 15, 1911, Application filed June 24, 1910. Serial No. 568,706. i

denser 0 condenser 0 coil L, spark gap a and condenser o The spark gap S arranged at any point between the aerial'con ductor and the earth makes it possible to watch the succession of single wave trains produced in the secondary circuit by the primary sparks, as each induced wave train produces a spark'at S. If each spark gap 8,, s 8,, is considered separately, it will be found that the frequency ofthe sparks for each gap is a determinate one This frequency is indicated b notewhlch the sparks produce, and is a function of the virtual lengths of the spark gaps, of the size of the'resistances, of the capacity, of thedamping coeflicient of the oscillation circuit, etc. All these factors are as far as possible, gap, and the capacity 0 can also be equal to the capacities c 0,, c o or be different therefrom. The resistances" r, r yr r are preferably made inductive, in

rent andin order to protect the dynamo from o cillations. It has been found that when in this device, '0 is not made-excessively large compared to a, 0, charges take place successively in all the spark gaps. The sequence of the primary sparks is automatically determined and the cycle of these discharges begins afresh, endlessly, at regular time intervals, so that the secondary wave 'trains' in the aerial conductor A, follow each other at given time intervals which are a multiple of the freand of the number of spark gaps. This can be proved by taking at S a spark from the aerial conductor, the said spark gives a musical-sound, the number of vibrations of which is equal to the product of the sound waves produced by each spark gap, by the number of the spark'gaps. This result was .vobserved from a low sound which correspo'nds to a few hundreds of sparks atS, up to the limit of audibility of high notes, and photographs of the spark gaps taken with a revolving mirror have shown regular sequences of equally spaced sparks of the order of 100,000 per second. The automatic, mutual influence of the consecutive the height of the quency of the discharges in each spark gap,

equal for. each -spark I order, to avoid strong fluctuations of cur- I o the disgaps 8 ,8 8

is thereby reduced, and thereforethe ten v sions are reduced at all the other spark 8,, which therefore do not discharge so long as there is a spark at 8,, but as soon as the said spark ceases the condenser 0 cominon to each capacity, (0 0,), (0,, c (0 o which are under charge respectively through the resistances r r from the lead N,'returning through lead M, increases rapidly in tension and thus raises the potential of each of the spark gaps by a common increment, while only the current arriving through the resistance r can charge the condenser 0 -All the condensers 0,, 0,, 0 o are already more or less charged but the condenser 0 has been just now completely discharged. Thus all the gaps s s s 8,, become operative consecutively before a can again dis charge and at the instants when the ,ten sion of 0, is each time high enough to break down one of these gaps after the other.' As now between two consecutive sparks in one and the same spark gap there must take place first a discharge at every one ofthe other gaps, it is clear that the discharges will take place in a regular sequence. These primary discharges induce in the secondary conductor Wave trains-as diagrammatically shown in Fig. 2 in which on a timeaxisZ are marked the wave trains by which four primary oscillation circuits 1),, 19 p 20 influence a secondary circuit. Between the Y beginning and end of two consecutive primary wave trains of one cycle there may be a time interval t, or theymay' overlap each,

other in time; it is sufficient to obtain overlapping to make the number of sparks per second sufiiciently great, and the damping .coeflicients :of their circuits small. This time-overlapping of the primary wave trains can be avoided in practice by the use of Wave trains following each other even at very short intervals provided that they quickly terminate, or conversely the number of 'sparks per time unit must be limited when they are of long duration, that is to say, their circuit'of oscillation has a'small damping coefiicient. I

, If there is a time interval between the end of one spark and the beginning of the next or between the spark cycles they may be made contiguous in time by arranging a common spark gap, which modification is shown in Fig. 3. The spark gap w.y is arranged between the individual plate of the condenser 0 and the primary induction coil L which is connected to one pole of the dynamo. As long as discharges take place at any of the spark gaps s s s, the gap wy will also be in the path of discharge and can be assumed to be conducting. If no discharge takes place in this arrangement, the result will be that, although the resistance of the ap may be small compared to that of the gaps s s s,,, as quantities of static electricity accumulate at a: and connected electrodes, owing to the current which comes direct from the supply lead M, and as these quantities. raise the small capacity of w, in a very short time to such a tension that a discharge must take place'somewherein the system, the latter does not take place' over w3 but over one of the gaps s 8 8,. The reason of this is that the individual plate of the capacity 0,

and-electrode g are completely insulated from the other pole of the machine. This, of course, would not be the case for alternating current, the small gap wy would be bridged over before the gaps 8,, s, 8

as with this kind of current electric quan- 1 a2,3 is not bridged over and would form a dielectric intermediate layer, this results in the isolation of a very small capacity at m and connected electrodes, and the potential would be increased so fast that a discharge would be brought about in almost infinitesimal time by one of the spark gaps 8 ,8 s,,. This function of the gap wy can be proven experimentally by providing cyclic disand duration that time intervals are produced between the single discharges, using for'the purpose a device such as shown in Fig. 1, and then switching in such a gap my. By' this intermediate switching there 'is at once-obtained an increase in the discharge frequency which will be at once reflected at S and contiguity in time between the single wave. trains will be effected; the sound produced in this .way at the spark at charge of primary sparksof such number wy has the same pitch as the spark S v (placed in the secondary,'as previously described in connection with Fig. 1) which has shown the increased frequency. of sparks upon the switching in of az-y. It is ob- VlOllS that when the gap a:y is to'work'as stated, its electrodes must be protected from overheating in order that the production of hot gases should not keep the gap permanently conducting. More particularly, when many primary oscillation circuits are used, which necessitate a great charging current, and. where wy is exposed to very powerful Oscillations which strongly heat the electrodes of the said gap, it is preferable to in-, sert between the free plates'or coatingsof the capacities c c c and their supply lead auxiliary spark gaps m 00 w similar in action to m-y (Fig. 4). As-long as a primary spark lasts,- its changing potential I afi e'cts 'all'the capacities and bridges all the gaps w, I ca but as soon as this strong source of oscillation ceases, the gaps m m m have the tendency to stop the supply of current to their capacities, this being chiefly the case for that capacity which is charged to the greatest extent, as its charging current is already automatically about to cease. The-most highly charged capacity is, therefore, first insulated through m :2 or :0 and therefore the dischargewill also take place first through the large'corresponding spark gap s s, or 8 To sum up, the object ofthevspark cycles 1 obtained by means 'of resistances and spark circuits connected inp'arallel in the fashion ping of a powerful aerial conductor capable should be abovethe audible notes.

'of giving'ofi' at once all the energy of each primary spark, it is 'suflicientfor wireless telephony that the spark periods in each circuit and the sequence of the said circuits Practical advantages can be obtained in wireless 'telegraphywhen the spark discharges of a cycle are rendered continuous,

and time intervals are left between the cycles. *In that way, groups of practically constant wave trains are produced inlthe secondary conductor. This result can be obtained by suitable selection of the several electric constants of the above circuits, notably the value of. 0

WhatI claim is:

1. An oscillatory system of circuits comprising in combination a plurality of spark gap circuits having a common inductance, a common condenser, and each a separate condenser with an armature in common with the common condenser, and means whereby the resulting capacities of each spark gap circuit may be charged.

2. An oscillatory system of circuits comprising in combination a plurality of spark gap circuits having a common inductance, a

common condenser, and each a separate condenser with an armature in common with the common condenser, and means whereby the resulting capacities of each spark gap circuit may be charged through a separate impedance from a common source ofdirect current. a

' 3. An oscillatory system of circuits comprising -in combination .a plurality of spark gap circuits having a common inductance, a

common condenser, and each a separate con- I denser with an armature in common with.

the common condenser, and means. whereby --.the resulting capacities. of each spark gap circuit may be charged through a separate impedance from a cpmmon source'of dlrcct current andv whereby the common condenser may be charged through all the separate condensers in parallel and through all these separate impedances in parallel respectively. 4. A secondary circuit and a primary oscillatory system of circuits comprising in combination a plurality of spark gap circuits having a common inductance, a common condenser, and each a separate condenser with an armature in commom with the common condenser, and means whereby the resulting capacities of each spark gap circuit may be charged. I 5. A device for producing continuous wave trains consisting of a secondary and a system ofprimary spark gap circuits comprising a'plurality of condensers, a common armature for all said condensers, a source of direct current, to EH16 pole of which one condenser" is connected by its individual armature and to the other pole of which all the other condensers are connected by .their individual armatures by "means of equal i-mpedances, and an oscillatory transformer having its primary connected to the common condenser, spark gaps arranged between the common condenser and each of the other condensers whereby the common condenser andthe primary of the transformerparticipate in allthe oscillations.of -'each of the primary spark gap circuits and influence the secondary of the oscillatory transformer.

6. A device for producing continuous wave trains consisting of a secondary and a.

system of primary spark gap circuits comprising a plurality of condensers, a common armature/for all said condensers, a source of direct current, to onefpole of which one condenser is connected by its individual armature and to the. other pole'of which all the other condensers are connected by their individual armatures by means of equal impedances, and an oscillatory transformer having its primary connected to the common condenser, spark gaps arranged between the common condenser and each of' the other condensers whereby the common condenser and the primary of the transformer participate in all the oscillations of each of the primary spark gap circuits and influence the name to this specification in the presence of secorlldary of till: oscillatory tI&Il11SfOI'I5leI',$Ild two subscribing Witnesses. auxi iar 5 ar an s between t e in ivi ual armaturi s of ea h of the plurality of con- ROBERTO GLEMENS'GALLETTI 5 densers and the points of connection of the Witnesses:

same with the source of current. MARIN VACHON,

In testimony vghereof I have signed my ANNA DE MESSIMY. 

